<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
	</head>
	<body>
	</body>
	<script type="text/javascript">
		//字面量
		console.log(1);
		
		//变量
		var a =1;
		a = a+1;
		console.log(a);
		
		//语义
		var age = 30;
		var age =31;
		console.log(age);
	</script>
</html>
